In a paper published in the Lancet, they report that participants receiving a first dose of Oxford-AstraZeneca or Pfizer-BioNTech generated a robust immune response when immunised nine weeks later with a second dose of COVID-19 vaccines manufactured by Novavax or Moderna. No safety concerns were raised in this study of 1,070 participants, who took part in the study across nine National Institute for Health Research-supported sites.
This study therefore supports flexible use of these vaccines in primary immunisation schedules, which is crucial to help rapid deployment of these vaccines, especially in low- and middle-income countries where vaccine supply may be inconsistent.